IN ALL OF THE ILLUSIONS YOU LOOKED AT THE LINES WERE PARALLEL. BELOW ARE EXPLANATIONS OF HOW YOUR BRAIN MIGHT HAVE INTERPRETED THE LINES
Cafe Wall Illusion
The horizontal lines in this image appear to be sloping, but in reality they're parallel to one another. Why does it work? Although it's easy to see the mortar line between two black tiles or two white tiles, it's much harder to see the mortar line between a white tile and a black one. Your brain fills in the gap by seeing it as part of either a white or black tile. This, in turn, makes the tiles look wider at one end than at the other, creating the illusion of a series of wedge-shaped tiles, which makes the lines appear to slant.
Zollner Illusion
In this figure the black lines seem to be nonparallel, but in reality they are parallel. The shorter lines are on an angle to the longer lines. This angle helps to create the impression that one end of the longer lines is nearer to the viewer than the other end. It may be that the Zöllner illusion is caused by this impression of depth.
The Herring Illusion
The straight lines in the illusion appear to bow out in the centre. This may be because you interpret the radiating lines in terms of depth, seeing the central spot in the Herring diagram as being further away than the edges. As a result, you believe that the heavy black lines must be further away in the centre as well. Because the heavy black lines are the same thickness at the centre as at the edges but are further away, your brain thinks they must be more widely spaced at the centre.